From: Brian Demsky <bdemsky@uci.edu>
Date: Mon, 16 Dec 2019 20:44:19 +0000 (-0800)
Subject: More code towards freeing old actions
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=98e8ab95688324f8d0c0e77392c375c89c562c08;p=c11tester.git

More code towards freeing old actions
---

diff --git a/action.cc b/action.cc
index 4c1630f4..814c7fb1 100644
--- a/action.cc
+++ b/action.cc
@@ -305,6 +305,11 @@ bool ModelAction::is_write() const
 	return type == ATOMIC_WRITE || type == ATOMIC_RMW || type == ATOMIC_INIT || type == NONATOMIC_WRITE;
 }
 
+bool ModelAction::is_free() const
+{
+	return type == READY_FREE;
+}
+
 bool ModelAction::could_be_write() const
 {
 	return is_write() || is_rmwr();
diff --git a/action.h b/action.h
index b7e6f479..95167c43 100644
--- a/action.h
+++ b/action.h
@@ -143,6 +143,7 @@ public:
 	bool is_atomic_var() const;
 	bool is_read() const;
 	bool is_write() const;
+	bool is_free() const;
 	bool is_yield() const;
 	bool could_be_write() const;
 	bool is_rmwr() const;
diff --git a/execution.cc b/execution.cc
index 1590d1c0..5aaabbcf 100644
--- a/execution.cc
+++ b/execution.cc
@@ -1697,7 +1697,7 @@ void ModelExecution::collectActions() {
 	//Compute minimal clock vector for all live threads
 	ClockVector *cvmin = computeMinimalCV();
 	SnapVector<CycleNode *> * queue = new SnapVector<CycleNode *>();
-	//walk action trace...  When we hit an action ,see if it is
+	//walk action trace...  When we hit an action, see if it is
 	//invisible (e.g., earlier than the first before the minimum
 	//clock for the thread...  if so erase it and all previous
 	//actions in cyclegraph
@@ -1731,6 +1731,52 @@ void ModelExecution::collectActions() {
 			}
 		}
 	}
+	for (sllnode<ModelAction*>* it = action_trace.end();it != NULL;it=it->getPrev()) {
+		ModelAction *act = it->getVal();
+		if (act->is_free()) {
+			removeAction(act);
+			delete act;
+		} else if (act->is_read()) {
+			if (act->get_reads_from()->is_free()) {
+				removeAction(act);
+				delete act;
+			} else {
+				const ModelAction *rel_fence =act->get_last_fence_release();
+				if (rel_fence != NULL) {
+					modelclock_t relfenceseq = rel_fence->get_seq_number();
+					thread_id_t relfence_tid = rel_fence->get_tid();
+					modelclock_t tid_clock = cvmin->getClock(relfence_tid);
+					//Remove references to irrelevant release fences
+					if (relfenceseq <= tid_clock)
+						act->set_last_fence_release(NULL);
+				}
+			}
+		} else if (act->is_fence()) {
+			//Note that acquire fences can always be safely
+			//removed, but could incur extra overheads in
+			//traversals.  Removing them before the cvmin seems
+			//like a good compromise.
+
+			//Release fences before the cvmin don't do anything
+			//because everyone has already synchronized.
+
+			//Sequentially fences before cvmin are redundant
+			//because happens-before will enforce same
+			//orderings.
+
+			modelclock_t actseq = act->get_seq_number();
+			thread_id_t act_tid = act->get_tid();
+			modelclock_t tid_clock = cvmin->getClock(act_tid);
+			if (actseq <= tid_clock) {
+				removeAction(act);
+				delete act;
+			}
+		} else {
+			//need to deal with lock, annotation, wait, notify, thread create, start, join, yield, finish
+			//lock, notify thread create, thread finish, yield, finish are dead as soon as they are in the trace
+			//need to keep most recent unlock/wait for each lock
+		}
+	}
 
 	delete cvmin;
 	delete queue;